Method for steam peeling plant products

ABSTRACT

A method for steam peeling a plant product selected from the group consisting of potatoes, carrots, celery, red beets, Swedish turnips and apples in a substantially cylindrical peeling vessel having a product opening at one end and a liquid discharge outlet at the other end. In the peeling vessel there is disposed a partition or grid at the liquid discharge outlet end perpendicular to the longitudinal axis thereof and spaced from the liquid discharge outlet. The partition prevents passage of product to be peeled while allowing condensate to pass therethrough such that the product does not lie in the condensate during the application of steam. The steam is applied through an access opening in the vessel which is above the product level when the vessel is tilted around a horizontal axis into a normally operating longitudinally inclined position. In order to effect the peeling operation during the application of steam, stirring is carried out by at least one stirring arm disposed above the partitioning and axially along the wall of the vessel. The stirring arm rotates about the longitudinal axis of the vessel, when the vessel is in the normally operating position, to effect the peeling of the plant product. The vessel later tilts around a horizontal axis from the normally operating position until the other end is above the one end for discharging the peeled product through the product opening.

This is a division of application Ser. No. 400,311 filed July 21, 1982,now U.S. Pat. No. 4,393,756, which is a continuation of application Ser.No. 235,368, filed Feb. 19, 1981, now abandoned, which is a continuationof application Ser. No. 104,990, filed Dec. 18, 1979, now abandoned.

The invention relates to a steam peeling or cooking apparatus forplants, such as potatoes, carrots, celery, red beets, Swedish turnips,apples and the like, or for pulp, provided with a substantiallycylindrical peeling vessel arranged rotatably about a horizontal shaft,having a supply or discharge opening disposed in one of the head faces,while the peeling vessel is furthermore provided with a steam supply ordischarge opening.

In such an apparatus disclosed in applicants' Dutch patent applicationNo. 76,11024 laid open to public inspection, the peeling vessel isrotatably mounted about the central axis. As a result, during operationwith a rotating peeling vessel, the plant to be peeled is intensivelycontacted with the pressure medium, in casu the steam, and stirred up.In this apparatus the steam supply and discharge takes place via ahollow shaft aligned with the central axis, in connection with therotation possibility of the peeling vessel. Furthermore the peelingvessel is arranged in a double frame in order to enable the aboverotation and a tilting of the vessel for the discharge of the product.

It is the object of the invention to simplify this prior art apparatusin such a way that it becomes cheaper and likewise resulting in anincreased safety of operation.

To this effect a steam peeling or cooking apparatus (to be referred tohereinafter as steam peeling apparatus) of the above described type, hasthe feature that the peeling vessel is provided with a stirring gearrotatable about the longitudinal axis. Said stirring gear may consist ofone or more rotatable arms or blades. It has been experimentally foundthat the plant to be peeled is properly stirred up for effecting anintensive contact thereof with the steam, without causing damage to theplant.

In a further embodiment of the steam peeling apparatus according to theinvention, the arms or blades may be secured to the rotatably mountedpartition if in the other head face positioned opposite the said headface fitted with a supply or discharge opening, a closable dischargeopening for the condensate is disposed and the portion adjacent thecondensate discharge opening is separated from the other portion of thepeeling vessel by a partition having one or more liquid passages,whereby the product and the condensate are kept separate.

The arms or blades may thereby be arranged adjacent the circumference ofthe peeling vessel, so that a minimal quantity of the plant to be peeledis in direct contact with the arms or blades.

Said partition may be designed as a grid, which is known per se.

Furthermore the steam supply or discharge opening may be disposedadjacent the top, and the supply or discharge opening of the peelingvessel and communicates via a curved tube section with a rotary couplingwhose rotation axis is aligned with the axis of the trunnions. As aresult a very simple tilting action is available for the peeling vesselfor discharging the plant and the peels.

Another possibility consists in that if in the other head face, which issituated opposite the head face provided with said supply or dischargeopening, there is provided a closable discharge opening for thecondensate and the portion in situ of the condensate discharge openingis separated from the other portion of the peeling vessel by a partitionhaving one or more liquid passages, the partition in this case, in theform of a grid has a stationary arrangement in the peeling vessel andthe arms or blades are attached to a coupling arm connected to a rotaryshaft.

Furthermore, the steam supply or discharge opening may be disposedadjacent the top and therefore adjacent the supply or discharge openingof the peeling vessel and, via a bent tube section, communicate with ahollow tube disposed beyond the centre of gravity of the vessel, whichtube likewise serves as axis of rotation of the vessel. As a result, thepeeling vessel, during tilting, is accelerated, respectively deceleratedthrough gravity, thus requiring slight mechanical forces for executingthe movement. Moreover, less bends and couplings are necessary, the wearis limited, while furthermore a quicker steam pressure reduction maytake place.

Some embodiments of the steam peeling apparatus according to theinvention will now be described, by way of example, with reference tothe accompanying drawings wherein:

FIG. 1 is a partial cross-section of a side view of a steam peelingapparatus;

FIG. 2 is a front view of the apparatus shown in FIG. 1, with omissionof some parts;

FIGS. 3 and 4 are views according to FIG. 1, respectively FIG. 2 of asecond embodiment of the steam peeling apparatus according to theinvention.

According to FIGS. 1 and 2 a steam peeling apparatus is provided with apeeling vessel 1 having trunnions 2 which are incorporated throughbearings 3 in a stationary frame, not shown.

The peeling vessel is provided at the top with a supply or dischargefunnel 4 for the plant. The closure of the funnel opening takes place bymeans of a cover 5 which may be operated by a piston-cylinder assembly 7by means of a lever 6 which is rotatably connected to the vessel. Asshown in FIG. 1 with dash-dotted lines, the cover 5 opens inwardly.

At the bottom the peeling vessel is provided for discharging condensate,sand and the like with a discharge 8 having a valve 9 which can beoperated by the piston rod of a piston-cylinder assembly 10.

In the peeling vessel there is disposed a partition or grid 11 dividingthe peeling vessel in two portions and which is provided with twoblade-like upwardly extending arms 12. The grid is secured to the end ofa shaft 13 arranged concentrically with the central axis of the vessel,which shaft extends through the bottom of the peeling vessel. The shaft13 is supported by two bearings 14, 15 which are attached to a seating16 connected to the peeling vessel. The sealing of the shaft 13 relativeto the bottom of the peeling vessel takes place by means of a knownstuffing box construction 17.

Between the two bearings 14 and 15 shaft 13 provided with a chain wheel18 or the like through which the shaft 13 may be driven by a chain, notshown, which is connected to the output shaft of a motor.

As mainly appears from FIG. 2 the peeling vessel is provided at the top,adjacent the supply or discharge funnel 4, with a steam supply ordischarge tube 19, which is connected to a rotary coupling 21 throughinterposition of a curved tube section 20. The latter coupling againcommunicates with a stationary manifold 22, communicating on the one endwith a steam supply 23 having a ball tap 24 and on the other end a steamdischarge 25 with a ball tap 26. Said manifold may furthermore beprovided with a condensate discharge 27 fitted with valve 28. The balltaps 24 and 26, as shown in the embodiment, may be operated via a lever29, 30 by a piston-cylinder assembly 31, 32 connected fixedly to theframe.

The operation of the apparatus seems clear after the above: Afterfilling the vessel with potatoes or the like, the cover 5 and the valve9 are closed. In closed position of the ball tap 26 and the valve 28,the ball tap 24 is opened for the supply of steam. After sufficientsteam has been supplied, the ball tap 24 is closed.

The shaft 13 with the grid 11 and the arms or blades 12 can be kept inrotational movement during the entire cycle. The meanwhile formedcondensate flows thereby downwards into the space underneath the grid,thus avoiding that the products are periodically immersed in therelatively cold condensate. After a specific, sufficiently longer periodof time, the ball tap 26 is opened and the steam is let off. After thisthe valve 9 is opened for discharging the condensate. Subsequently thecylinder 7 is operated for opening the cover 5, after which the peelingvessel is tilted by means, not shown, until the funnel 4 has reached theposition shown in FIG. 1 with dash-dotted lines, while meanwhile theplant and the peels are discharged slidingly. Hereafter the peelingvessel is returned to the starting position, after which the next cyclemay be initiated.

By eliminating a number of functions relative to the apparatus disclosedin Dutch patent application No. 76,11024 of applicants, a shorter cycleperiod and a simplified control are obtained so that naturally also thecosts of manufacture are reduced.

Moreover the protection is improved, while furthermore a more intensiveturbulence of the plant is achieved. Another advantage is that a higherdegree of filling is possible than is the case with the prior artapparatus.

Of the second embodiment to be described by means of FIGS. 3 and 4,wherein the same parts are indicated by the same reference numerals,only those parts will be described that differ from those of the firstembodiment.

In the second embodiment the suspension of the peeling vessel is changedin such a manner that the vessel during tilting is accelerated,respectively decelerated through gravity. As a result, smallermechanical forces are required at the same time of motion for performingsaid motion. Said tilting takes place about a hollow shaft 33. To saidhollow shaft connects a bend 34 via which steam may be supplied to ordischarged from the vessel. This has the advantage during dischargethat, since the inlet of the discharge is maximally spaced apart fromthe product level, entrainment of peels and the like is substantiallyprevented. On the other hand, a maximal product level is achievedthereby. It is observed in this respect that the attachment of thehollow shaft and the bend takes place by means of a seating 35 welded onthe vessel. To said seating there is likewise secured the cylinder 7adapted for operation of the cover 5.

By the above described combination of suspension of the vessel and thesteam supply and discharge, a completely centered steam connecting pipewithout bends is possible. As a result, not only less wear on thefittings is achieved, but likewise a quicker steam pressure reduction.

An other major difference relatively to the first embodiment consists inthat the grid 11 is affixed to the peeling vessel and the arms 12 areattached to a coupling arm 36 mounted on shaft 13. Thus, only the lowerportion of the grid 11 need be designed as grid (for passingcondensate), while the other portion may be closed. As a result, abetter movement of the products relatively to each other will beachieved, for they can no longer co-rotate with the grid. Besides, sincethe grid is substantially closed the product is smooth and therefore isnot further scraped, so that a substantially lower pollution of thecondensing water is produced.

A further modification relatively to the first embodiment is formed inthat the shape of the vessel is slightly altered in the sense that thewall portion over which the products move during supply, resp.discharge, is straight and not, as in FIGS. 1 and 2, bottle-neck-shaped.This facilitates the emptying of the peeling vessel.

What I claim is:
 1. A method of steam peeling a plant product selectedfrom the group consisting of potatoes, carrots, celery, red beets,Swedish turnips and apples, comprising the steps of:introducing saidplant product to be peeled through a product opening at one end of asubstantially cylindrical peeling vessel having a liquid dischargeoutlet at the other end; tilting the vessel around a horizontal axisinto a normally operating longitudinally inclined position wherein theone end is above the other end to a discharge outlet and productopening; partitioning the vessel at said other end perpendicular to thelongitudinal axis thereof and spaced from the liquid discharge outlet,when the vessel is in the normally operating position, to preventpassage of product to be peeled while allowing condensate to passtherethrough such that the product to be peeled does not lie in thecondensate during the application of steam; applying steam through anaccess opening in the vessel disposed above the product level while thevessel is in the normally operating position, via a first steam linedisposed colinearly with the horizontal tilting axis and a second lineconnecting the first line to the access opening; stirring the productduring the application of steam by at least one stirring arm disposedabove the partitioning and axially along the wall of the vessel androtating about the longitudinal axis of the vessel to effect the peelingof the plant product; collecting the condensate below the partitioningand discharging same after the application of the steam; and tilting thevessel from the horizontal axis from the normally operating positionuntil the other end is above the one end and discharging the peeledproduct through the product opening.